Abstract: From 1953 to 1955, studies on the relation between the spike formation and the stage development of two varieties of wheat (spring wheat 2419 and winter wheat "Hsiao-Hung-Moun") has been carried out at Shanghai. The results of these experiments may be summarized as follows: 1. When sowned in autumn, the growing cones of both varieties of wheat were not elongated at the end of the thermo-stage. 2. Winter wheat "Hsiao-Hung-Moun", either sowned in spring with vernalized seeds or sowned in autumn, and spring wheat 2419 sowned in spring with vernalized seeds, completed their photo-stage in the course of the formation of stamens and pistils. 3. The striking effect of the day-length on the differentiation of the growing cones of both varieties of wheat, either sowned in spring with vernalized seeds or sowned in autumn, was observed in periods from the elongation of the growing cone to the formation of the primodia of spikelets. The longer the day length, the earlier the differentiation of the growing cones. 4. Different treatment with varied length of light of the planks, before the elongation of their growing cones, influenced the rate of the later stages of the differentiation of the growing cones, 24-hour illumination accelerated this process.